The overall objective of the MR Spectrometry Core (C) is to develop and apply multinuclear Nuclear Magnetic Resonance (NMR) spectrometry and imaging core facilities for the study of hypoxic-ischemic brain damage in immature experimental animals. The spectroscopy component of the Core will develop NMR spectroscopy techniques to evaluate metabolic alterations which occur during and following cerebral hypoxia-ischemia in immature rats and newborn dogs. Spatially localized 31P and 1H NMR spectroscopy will be used to quantitate changes in lactate concentrations, energy metabolism, intracellular pH and free cytosolic magnesium concentrations. We have developed a new iterative method to determine more accurately intracellular pH and free magnesium (Mg++) concentrations using the 3 resonances of ATP. The imaging component of the Core will develop and apply magnetic resonance imaging (MRI) techniques to evaluate perinatal hypoxic-ischemic brain damage. Central to the research will be the characterization of the normal developing rat brain. Two imaging techniques will be used to elucidate the sites and severities of brain damage at different states of hypoxia-ischemia and recovery. These techniques include diffusion and T2-weighted spin echo imaging. Preliminary results indicate that diffusion imaging is a sensitive method for early detection of hypoxic- ischemic injury, while T2-weighted spin echo imaging more accurately monitors long-term damage. Animal movement restraining devices essential to obtaining reliable diffusion images will be continually designed, constructed and refined. These devices will be incorporated into the general probe design for spectroscopy or imaging for each research project (Projects 1,3,4)